sweet potato mash experiment

Any updates? Super interested in this thread!!!!

Hi - I'm brewing today as my beer-fridge is running low... Sorry, the updates are long overdue.

The 'experiments' have been successful. We've been enjoying a variety of dark, light, bitter, and ginger beer based primarily on sweet potato and buckwheat.

Since measuring alcohol yield, I've seen values between 3.5 and 5%. I'm not going for high alcohol content mind you, the 5% was made special for the fianc? .

Happy to swap ideas, let me know if you have suggestions or questions.

I would like to see recipes, yeilds, and tasting notes. How do they stack up to other gluten free beers?

Thanks for the update funky!

hey all, I've been searching for sweet potato mash schedules and found this... I tried something similar, 2 lbs, through a food processor, 155F for 1 hr in 2 gal of water, drain water, add another gallon of water, boil 20 min, drain water and return to other two gallons. blended rest of potatoes and added them into the now 3 gallons. Added 1/2 tsp of alpha amalyse, and 1/2 tsp of beta amalyse. held at 155 for 30 min. strained out solids, boiled down to about 1.5 gal. put in carboy after fall out (very heavy fall out) about 1 gallon.... 1.030. that puts my efficiency at 37%. meaning I got .75lbs of sugar out of a possible ~2lbs. anyone got any ideas?

Why on earth would you go through all that trouble if you're just going to add enzymes anyway? I thought the whole point of using sweet potatoes was to capitalize on their native enzymes?

I think your math may be a little funny, too. Where are you getting 37% efficiency? What is the estimated PPG for sweet potatoes that you are basing that off of?

He drained off some liquid w/ enzymes and added it back after the boil. I can't tell if cooled it down before adding the liquid back.
I'm also not following the efficiency math. The gravity he got is about where I ended when I experimented with sweet potatoes.

I did cool the wort before adding it back in with the already extracted wort. I would agree with the enzyme comment.... I haven't been doing the all grain very long and wanted to give myself a top amount to shoot for (ie make sure I wasn't screwing it up. I don't have any PPG info on sweet potatoes.... I did some back of the napkin math..... Long story short I screwed up the math. I agree I'm in the ball park I should be in. Another question then to pose to the group, any good ideas as far as recipes for making a sweet potato beer? Thanks for the correction.

I made a "paleo" beer with a combo of sweet potato, chestnuts, agave nectar, and honey once. Fermented it with WB-06, very lightly hopped. Great summer quencher...went REAL fast, LOL. I mashed the chestnuts and sweet potatoes with amylase after boiling them. The beer was very light, smooth, crisp, and a little fruity.

burns7aj said:

I did cool the wort before adding it back in with the already extracted wort. I would agree with the enzyme comment.... I haven't been doing the all grain very long and wanted to give myself a top amount to shoot for (ie make sure I wasn't screwing it up. I don't have any PPG info on sweet potatoes.... I did some back of the napkin math..... Long story short I screwed up the math. I agree I'm in the ball park I should be in. Another question then to pose to the group, any good ideas as far as recipes for making a sweet potato beer? Thanks for the correction.

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I've only tried it the one time. I got a soapy flavor, which I think came from the fat in the troub. My advice would be to secondary and not let it sit on the troub.

As far as recipe, I didn't try anything fancy. I purposely kept it light so that I could get an idea of what the sweet potatos were bringing to the table. It was fizzy, yellow and sweet. Great for a hot day, but I'm still not sure what I'd add to it. It's got some of it's own flavor going on, but not so much that it's crying out to be a spiced beer. I think it'd be best blended with sorghum syrup or if you could use it to help convert other GF grains.

aomagman78, I used a similar method. I shredded 8lbs in a food processor, held at 152F for 1 hr with 2 gal, drained the 2 gal, then added one more, boiled for 30 min and then "mashed the potatoes" added everything back in and held at 152F another 1hr this time with some alpha and beta amalyse. my OG for the gallon I had left after boil (after the massive fallout) was 1.030. when I use numbers like yours, assume 25% starch, that puts me around 37%. also, there was WAY too much potatoes left. i'm not sure where I went wrong. let me know how yours works.

I purchased some white milet malt and after a couple of experiments I determined it was not properly malted and could only convert about 75%.
Also I wanted to make a millet Chestnut ale similar to a brown English ale.

The Chestnut chips where given a rest at 122 for 8 hours with Pectin and Amalyse enzyme added,
I Ran 5 lbs of Sweet potato in my food processer to a course grind so it wouldn't create a stuck mash.
I just wanted the Enzymes and was not concerned about extracting the sugars or starch from the potatos.
I put the sweet potatoes in an oven set to 145, inside a turkey bag. for 4 hours
I then meshed my grains using the Chestnut extract at 150, and added the sweet potato mash. Then let it rest for 90 minutes. At this point it passed the Iodine test.
Note: I peeled the sweet potatos and added additional Alpha Amalyse to the mash. Perhaps the soapy flavor comes from the Skins.
Also I did not try to gelatinize the sweet potatoes

Recipe - 4 gallons
6 lbs Millet Malt
1 lb Oat Malt
1/2 lb Sprouted Quinoa (From Whole foods)
The above grains where given a 122 protein rest for 30 min
4 lbs Med Chestnut chips
5 lbs Course Ground Sweet Potatoes
1 tsp alpha amalyse enzyme
All the above where Mashed at 150 for 90 minuites Then passed Starch test
Used RO water (similar to distilled) for the above, PH was 5.4
Sparged with RO water
Steeped 30 min @ 150, with 1 gal. Med hard water, 1 lb Millet Crystal, 1 lb Med Toasted Buckwheat both about 90L, PH 5.6) and added to boil
Did typical 60 min boil with hops added @ 60, 15, 5
Irish Moss @ 15
Pre Boil volume 5 gallons, Final Volume 4 gallons
OG 1.052
IBU 16
SRM about 15

The Sweet Potato worked well to complete the starch conversion. I tried a similar recipe w/o sweet potato and ended up with over 2 oz of starch per gallon.
Taste test of wort, malty, earthy, caramel, coffee, smoky with bitter, nutty after taste.

I noted a lot of people here where giving the sweet potatoes a protein rest at 122, not sure why as sweet potatoes are very low in protein, I do not believe this accomplishes anything.

The use of sweet potatoes is very interesting! Curious why you steeped the crystal and buckwheat separately rather than just mashing with the rest of the grain.

glutarded-chris said:

The use of sweet potatoes is very interesting! Curious why you steeped the crystal and buckwheat separately rather than just mashing with the rest of the grain.

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Maybe to help prevent a stuck sparge because of the buckwheat. He wasn't in gel range for the buckwheat anyway so he wasn't going to get much from it.

Curious where the oat malt cam from. AiH?

I don't brew gf however after reading this thread i wonder if a 50-50 mash of raw adjunct and sweet potato as an enhanced double decoction would enter into the realm of delicious?

mash in around 35c @ 3L/KG, draw off 60-70% of the mash liqour and boil the **** out of the mash then add back to bring it through the mash range over the course of an hour.

I only wanted the color and flavor from the crystal and buckwheat. I also was using a lot of buckwheat seed which have the hulls. not just grouts, so I didn't want the tannins. That is why I steeped separately.

I don't think Sweet Potato has much Alpha enzyme. It has some just under its skin and has a lot of beta enzyme through out it's meat. Also many reported brewing with sweet potato resulted in a soapy taste where they used unpeeled and then gelatinzed them. I peal my sweet potato and don't bother to gelatinize. I also add alpha enzyme. Seems to have good conversion power without off flavors. I don't know the DP of sweet potato, so I can't say if it can convert 50% adjunct. If I wasn't doing GF or low gluten I would use 6 row instead of sweet potato and use a protein rest for the adjuncts.

Depending on your use of the sweetpotato you may not need to mash it. If you roast it, you needn't mash it. When you roast the sweetpotato, what you are essentially doing is mashing it, only with dry heat instead of in water. The only real purpose of the water in the mash process is to distribute the enzymes for contact with the starches and collect the resulting sugars. Roasting the sweetpotato temperature activates the amylase enzymes and converts the starches to fermentable sugars. The best yields are going to come from starchy varieties, like the yellow or cream-fleshed specimens. The normal table-fare (typically beauregard) won't yield as well, but will give you a more familiar flavor.

There is a lot of confusion between sweet potatoes and yams. Everything you find in the typical grocery store in the US weather labeled sweet potato or yam is a sweet potato. True yams are rarely found in the US, and will have a dark bark like skin, and white to purple flesh. The sweet potatoes we see labeled sweet potatoes or yams, are just two different varieties of sweet potato with slightly different colors and one having a firmer flesh than the other. These are all tubers in the same family as the Morning Glory, where the true yam, which most of us have never seen, is an African tuber from the Lilly family. The skin of a true yam is a dead give away, and will quite dark and scaly, more like bark.


H.W.

I'm trying a different twist on sweet potato ale at the moment. I'm slow cooking sweet potatoes at just under a boil for several hours, and will run them through the blender drain the liquid off and use it with my strike water in a very light brew. The pulp will be saved, and added in a bag at the end of the boil, and go into the fermenter. I'll not worry too much about conversion, but instead, I'll add STC 1000 in the fermenter. This brew will contain only sweet potato (called yam), 2 row, and invert sugar, and will be hopped only to about 20 IBU.

H.W.

I took down some notes on my quick and dirty sweet potato experiment here:

https://www.reddit.com/r/Homebrewing/comments/6fdz2o/another_sweet_potato_beer_experiment/

Comments/questions welcome. Messed with a couple of things to overcome the purpleness but hadn't really prepared

burns7aj said:

aomagman78, I used a similar method. I shredded 8lbs in a food processor, held at 152F for 1 hr with 2 gal, drained the 2 gal, then added one more, boiled for 30 min and then "mashed the potatoes" added everything back in and held at 152F another 1hr this time with some alpha and beta amalyse. my OG for the gallon I had left after boil (after the massive fallout) was 1.030. when I use numbers like yours, assume 25% starch, that puts me around 37%. also, there was WAY too much potatoes left. i'm not sure where I went wrong. let me know how yours works.

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I did something similar for an all sweet potato beer (added 8oz of 6 row for enzyme activity just in case). I peeled, grated sweet potato. Held at 140F in 'mash' step, removed sweet potatoes from water, and boiled separately. Put the boiled sweet potatoes in a blender, and returned to mash now at 152F for 90min. I ended up at 1.048 (2.5 gal) with 6 kilos of grated potato. Added Saaz, and S04 which devoured the sugars, leaving me at 1.004. I pulled it off the trub (lots of it) within 10 days, as suggested previously.
Any suggestions on flavorings for secondary? I'm splitting my batch into several 1 gallon secondaries to test some ideas. I want to stay away from pumpkin pie, as I already made one for fall.